It is now conventional to install well tools, typically multiple string tubing hangers, in underwater well installations by remote operations carried out from a vessel, platform or like operational base at the surface of the body of water, with the well tool being landed remotely by use of a handling string and a guidance system, and then rotated, by manipulating the handling string, to bring the tool into a predetermined rotational orientation. According to usual practices, the well installation is equipped with a member, typically a wellhead upper body, having an upright internal locator slot which, due to installation of that member with the aid of the guidance system, has a known rotational orientation. The well tool is then landed by means including a spring biased locator key, using the guidance system to assure that the locator key is displaced counterclockwise from the locator slot. By manipulation of the handling string, the well tool is then rotated clockwise until a marked increase in torque occurs, such increase being an ambiguous indication that the locator key of the tool has snapped into the locator slot of the wellhead body or other member. Since the torque increase could occur for other reasons, the handling string is withdrawn, turned clockwise to displace the locator key from the locator slot in a clockwise direction, then lowered to reland the well tool and then rotated counterclockwise to bring the key again to the slot. Then, if an increase in torque again occurs, it is concluded that the locator key is engaged in the locator slot. While accepted, such procedures leave much to be desired, since even existence of two occurrences of torque increase is at best an indication subject to significant ambiguity.